Electromagnetic relay



H. B. TAYLOR ELEGTROMAGNETIC RELAY Filed March 30, 1951 Sept. 13, 1932.

d 1 M e l o Patented Sept.` 13,v 1932 L UNITED sTATEs PATENT OFFICE HERBERT B. TAYLOR, 0F ROCHESTER, NEWYORX, ASSIGNOR T0 GENERAL RAILWAY l SIGNAL COMPANY, QEBDCHESTEB, NEW 'YORK ELECTROMAGNETIC RELAY Application led March 30, 1931. Serial No. 526,190.

This invention relates to electro-magnetic relays and more particularly to adjustable slow acting relays. v

The usual type of electro-magnetic relay has a characteristic fast act-ion which is not adapted to certain circuit arrangements, such as are occasionally involved in railway signalling practice, as such circuits require a delinite time element in their operation to the energized position or the de-energized position, as required. There are several well known means of increasing the acting time of such relays by retarding the building up of the operating force but such means are ineffective to suliic-iently delay the operation for the above mentioned circuits. Sulicient time element may be obtained however by retarding the operating action itself through the use of an auxiliary device, such'as a dash pot, connected to 'the armature of the relay. However, such auxiliary apparatus unduly complicates the relay and. introduces losses due to friction thereby generally increases the required amount of operating power. t

In view of the above, it is proposed in accordance with this invention to incorporate a retarding element as a part of the relay itself so that the apparatus is not materially complicated. It is also proposed to provide such a retarding element which may be employed in a relay to complete a circuit after a predetermined lapse of time or in a similar relay to interrupt a circuit after apredetermined lapse of time.

Other objects, purposes and characteristic features of the present invention will appear as the description thereof progresses, during which references will be made to the accompanying drawing which shows the invention lC in a manner to make it easily understood,

rather than 'with the view of showing the particular construction preferably employed in practice, and in which Fig. l1 is a sectional view of a relayaccording to this invention. f

Fig. 2 is a sectional view of a modified form of relay also according to this invention.

Fig. 3 is a view of a proposed means of reversing the operating characteristics` of either the relay of Fig. 1 or Fig. 2.v

proposed The receptacle R holds mercury, or like material, M therein of a suitable quantity to have a level below the inwardly projecting ends of the contact strips 1 and 2. An iron cylinder C, which loosely fits inside the receptacle R is arranged to float in the mercury M to such a depth as not to raise the mercury level to the contact strips 1 and 2.

The top of the iron cylinder C is closed, except fora round tapering hole in the center which forms a seat S for a ball valve V. A strip 3, secured to the cylinder C, is arranged to retain the valve V adjacent its seat S, and still allow a slight lifting of the valve therefrom. A small vent O is included in the side of the cylinder C to admit air into the hollow of the cylinder C, and consequently its size determines the operating delay of the relay,

@as is hereinafter fully described.

The top of the receptacleR is covered' bly a cap 4 which is held thereon by suitable sea ing compound 5, as shown. The floating poya nut 7. This screw 6 projects` through the cap 4and is engageable' with the l top offthe valve retaining strip 3 for thereby regulating the floating height of the cylinder and consequently determining the level of the mercury in the receptacle R. ,l

Thelower end of receptacle Ris held' in a. depression ina base B which ma belined with a soft material 8, such as fe t, to protect the receptacle when made of fragile ma- 1 terial. The lower portion of the receptacle R is surrounded by amagnet coil MC which is held to the base by an'iron case 9 covering the sides'and toplthereof. 'This case 9 maybe suitably held to the base yB by 'and vthe top extends 'to the side of the receptwo screws 10 cylinder C which orces the ball valve V upward, thereby allowing a free passage of air out of the cylinder C without materially retarding the motion of the cylinder into the mercury M. This downward motion of the cylinder C in the receptacle R, displaces the mercury M, causing its level to rise until it bridges the inner ends of the contact strips 1 and 2, thereby completing an electrical connection therebetween. A washer 11made of `suitable material such as cork, is placed at the bottom of the receptacle R to absorb the shock at the end of the cylinder travel to thereby prevent breaking of the receptacle R.

Upon de-energization of the magnet coil MC the buoyancy of the mercury tends to raise the cylinder Cin the receptacle R and preate a vacuum therein, as the ball valve V 1s drawn down against its seat S. This retards the upward motion of the cylinder, which can rise only as air is slowly admitted thereinto through vent O, whereby the cylinder. returns but slowly to its top position, to lower the mercury and open the controlled circuit.

Thus the relay just described is operable to quickly complete a circuit, on energization and to interrupt the circuit only after a predetermined lapse of time after de-energization. The reverse of this operation is often desirable, and can be obtained by inverting the arrangement of the ball valve V in the top of the 'cylinder C, as is shown in Fig. 3.

The ball valve V1, in the arrangement shown Iin Fig. 3, is constructed of a lightweight material such as vulcanized rubber, and is held 1n its normal downward position Aby a retaining strip 31. The operation of such a relay creates an air pressure within the cylinder C1 during the downward motion thereof which orcesthe `ball valve V1 upwardinto its seat S1. This prevents the pas sage of air through the top port but allows it'to slowly escape through the small vent O1, which retards the downward motion of the cylinder C1 when the magnet coil MC is energized. The cylinder C1 is obviously allowed to return to its top position rapidly as the ball valve V1 is then in its lower position allowing the air to pass freely through the top port.

The modified form of this relay shown in Fig. 2 employs the same cylinder C and consequently the retarding action can be the same in either case, and the inverted valve arrangement, just described in Fig. 3, is equally applicable thereto. The major difference in the modified form of Fig. 2 is the upwardly extending iron core B2, which slightly alters the operating characteristics of the relay. This iron core B2 is cone-shaped which provides a decreasing air gap between its side and the side of the cylinder C as the cylinder is drawn downwardly, and thereby accelerates the action toward the end of the down stroke.

Other slight modifications are shown in Fig. 2 such as the moulded insulating recep- F tacle R2 which is threaded at its lower end to the base B1 and also threaded at its upper end to receive the cap 41. The iron base 91 surrounding themagnet coil MC may also be threaded on the base B1, as shown, and its top opening arranged to tit closely around the receptacle R1' to provide an etiicient magnetic circuit as well as a compact and rugged construction.

It will now be seen that a relay has been provided which can be arranged to produce a. time delay in its action either in closing or interrupting a circuit, and it is also feasible to construct the relay without the ball valve arrangement, so as to have both its operating actions retarded as determined by the passage of air through a small vent, as vent O. When this relay is arranged to interrupt a circuit after a predetermined lapse of time, such operating time is obviously unaffected by any variations in operating voltage, and such variations can only slightly alter the operating time of a relay which is arranged to close a circuit after a predetermined lapse of time.

The receptacle R and R may be made of iron' with the contacts insulated therefrom, instead of glass, or molded insulating material, as shown. The number of the contacts may also be increased, if a large current is to be carried, and it may also be found expedient in preventing corrosion of the contacts or the hke to till the receptacle with a gas and seal the top after adjustments have been made.

The above description, of the present invention is given solely by the way of example, and is not intended, in any manner whatsoever, in a limiting sense. It is also to be understood that various modifications, adaptations and alterations may be applied to meet the requirements of practice, without in any manner departing from the spirit or scope of thepresent invention, except as limited by the appended claims.`

Y Having thus described my invention, what Il claim is 1. In an electro-magnetic relay, a` solenoid having a core containing mercury, an inverted cup of magnetic materialloating in said mercury, means in said cup to pass air win a single direction and said cup being operable by energizing said solenoid to disp ace said mercury whereby electrical contacts are bridged.'`

der being closed at its top, except for a small l vent, by a check valve. l

3. In an electro-magnetic relay, a nonmagnetic receptacle carrying spaced dn,- sulated contacts, mercury in said receptacle, an inverted cup of magnetic material floating in said mercury arranged to partially trap air therein, a small hole in said cu a check air valve in said cup and a solenoi operable to attract said cu thereby displacing said mercury to a level bridging said contacts.

4. In a ytime element relay, an iron clad electro-magnet, a mercury holding receptacle in the core of said electro-magnet, insulated electrical contacts extending within said receptacle 4above the level of said mercury, an inverted iron cup floating in said Vmercury and attractable therein by the energization of said electro-magnet and means in said cup permitting the passage of air therefrom in a sin le directio 5. n a time element relay, an electromagnet, a mercury holding receptacle in the core of said electro-magnet, insulated contacts extending within said receptacle above said mercury, a hollow plunger of magnetic material attractable by said electro-magnet to displace said mercury, means in said hol low iron plunger to create an air pressure therein when thus' attracted and a vent for slowly releasing said air pressure.

'6. In a time element relay, an electromagnet, a mercury holding receptacle in the core of said electro-magnet, insulated con-` tacts extending within said receptacle above lsaid mercury, a hollow plunger of magnetic material normally floating in said mercury and attractable downwardly therein by said electromagnet, means in said hollow iron plunger to create arpartial vacuum therein when returning to said normal floating position and a vent for slowly admitting air to said Vacuum.

7. In an electro-magnetic relayan operating coil, a body of mercury in a receptacle in the core of said coil, a cone-shaped iron core in said receptacle, an iron cylinder in said mercury buoyed against lan adjustable stop in said receptacle, insulated contacts extending within saidreceptacle and above the normal-level of said mercury, a yvalve port. in the top of said'cylinder, and a check -ball valve controlling said port. 4

In testimony whereof I affix mysignature.

HERBERT B. TAYLOR. 

